1,2-Dichlorobenzene, or orthodichlorobenzene (ODCB), is an

aryl chloride In organic chemistry, an aryl halide (also known as a haloarene) is an aromatic compound in which one or more hydrogen atoms directly bonded to an aromatic ring are replaced by a halide ion (such as fluorine F''−'', chlorine Cl−1,−3,−5, bro ...

and isomer of

dichlorobenzene There are three distinct chemical compounds which are dichlorobenzenes: * 1,2-Dichlorobenzene or ''ortho''-dichlorobenzene; * 1,3-Dichlorobenzene or ''meta''-dichlorobenzene; * 1,4-Dichlorobenzene or ''para''-dichlorobenzene. All three isomers are ...

with the formula CHCl. This colourless liquid is poorly soluble in water but miscible with most organic solvents. It is a derivative of

benzene Benzene is an Organic compound, organic chemical compound with the Chemical formula#Molecular formula, molecular formula C6H6. The benzene molecule is composed of six carbon atoms joined in a planar hexagonal Ring (chemistry), ring with one hyd ...

, consisting of two adjacent

chlorine Chlorine is a chemical element; it has Symbol (chemistry), symbol Cl and atomic number 17. The second-lightest of the halogens, it appears between fluorine and bromine in the periodic table and its properties are mostly intermediate between ...

atoms. It is mainly used as a

precursor chemical In chemistry, a precursor is a compound that participates in a chemical reaction that produces another compound. In biochemistry, the term "precursor" often refers more specifically to a chemical compound preceding another in a metabolic pathway, ...

in the synthesis of

agrochemical An agrochemical or agrichemical, a contraction of ''agricultural chemical'', is a chemical product used in industrial agriculture. Agrichemical typically refers to biocides (pesticides including insecticides, herbicides, fungicides and nematicide ...

s, as a preferred solvent for dissolving and working with

fullerene A fullerene is an allotropes of carbon, allotrope of carbon whose molecules consist of carbon atoms connected by single and double bonds so as to form a closed or partially closed mesh, with fused rings of five to six atoms. The molecules may ...

s, as an

insecticide Insecticides are pesticides used to kill insects. They include ovicides and larvicides used against insect eggs and larvae, respectively. The major use of insecticides is in agriculture, but they are also used in home and garden settings, i ...

, and in softening and removing carbon-based contamination on metal surfaces.

Production and uses

1,2-Dichlorobenzene is obtained as a side-product of the production of

chlorobenzene Chlorobenzene (abbreviated PhCl) is an aryl chloride and the simplest of the chlorobenzenes, consisting of a benzene ring substituted with one chlorine atom. Its chemical formula is C6H5Cl. This colorless, flammable liquid is a common solvent a ...

: : + → + HCl The reaction also affords the 1,4- and small amounts of the 1,3-isomer. The 1,4- isomer is preferred over the 1,2- isomer due to

steric hindrance Steric effects arise from the spatial arrangement of atoms. When atoms come close together there is generally a rise in the energy of the molecule. Steric effects are nonbonding interactions that influence the shape ( conformation) and reactivi ...

. The 1,3- isomer is uncommon because it is a meta- compound, while chlorine, like all halogens, is an ortho/para- director in terms of

electrophilic aromatic substitution Electrophilic aromatic substitution (SEAr) is an organic reaction in which an atom that is attached to an aromatic ring, aromatic system (usually hydrogen) is replaced by an electrophile. Some of the most important electrophilic aromatic substitut ...

. It is mainly used as a precursor to 1,2-dichloro-4-nitrobenzene, an intermediate in the synthesis of

s.Gerald Booth (2007). "Nitro Compounds, Aromatic" in ''Ullmann's Encyclopedia of Industrial Chemistry'' Wiley-VCH, Weinheim, 2005. In terms of niche applications, 1,2-dichlorobenzene is a versatile, high-boiling solvent. It is a preferred solvent for dissolving and working with

s. It is an

for termites and locust borers, historically used by the

United States Forest Service The United States Forest Service (USFS) is an agency within the United States Department of Agriculture, U.S. Department of Agriculture. It administers the nation's 154 United States National Forest, national forests and 20 United States Natio ...

to combat widespread bark beetle outbreaks. 1,2-Dichlorobenzene is also used in softening and removing carbon-based contamination on metal surfaces.

Safety

Data from human exposure to 1,2-dichlorobenzene shows that concentrations of 100 ppm have been reported to cause sporadic irritation of the eyes and respiratory tract. The

Occupational Safety and Health Administration The Occupational Safety and Health Administration (OSHA; ) is a regulatory agency of the United States Department of Labor that originally had federal visitorial powers to inspect and examine workplaces. The United States Congress established ...

and the

National Institute for Occupational Safety and Health The National Institute for Occupational Safety and Health (NIOSH, ) is the List of United States federal agencies, United States federal agency responsible for conducting research and making recommendations for the prevention of work-related occ ...

have set occupational exposure limits at a ceiling of 50 ppm, over an eight-hour workday.

References

{{DEFAULTSORT:Dichlorobenzene, 1, 2- Chlorobenzenes Organochloride insecticides Halogenated solvents Aromatic solvents

Production and uses

Safety

See also

References